Figure 2.

Transcription activity of RNAPs containing mutant σ⁷⁰ subunits on the T7A1 promoter. (A) Full-length RNA synthesis on the T7A1 promoter template. Positions of the terminated (tR2) and full-length run-off (RO) transcripts are indicated. Reactions contained 10 µM ATP, CTP, GTP and 5 µM UTP; RNA primer CpA was added when indicated. Relative activities of wild-type and mutant RNAPs, calculated as a sum of tR2 and RO transcripts, are shown below the gel (averages and standard deviations from three independent experiments). (B) RNAP activities on the T7A1 promoter template in the presence of various initiating primers (lanes 1–12) and at high NTP concentrations (200 µM ATP, CTP, GTP and 10 µM UTP) (lanes 13–20). Positions of the tR2 and RO transcripts are indicated.